1. Field of the Invention
The invention relates to rack structures and a method of producing the same and somewhat more particularly to Si or SiC crystal wafer rack structures which support crystal wafers during diffusion doping and/or annealing procedures and a method of producing the same.
2. Prior Art
Si or SiC rack structures of the type required for diffusion doping and/or annealing procedures on crystal wafers, such as silicon wafers which are useful in semiconductor technology, are superior in terms of temperature stability and purity of environment in relation to comparable and more conventional quartz rack structures. However, Si or SiC rack structures are extremely difficult and expensive to produce from solid Si or SiC bodies.
Methods of manufacturing tubes or hollow bodies composed of semiconductor materials by a gas phase pyrolytic deposition of semiconductor materials is known. For example, German Offenlegungsschrift 21 25 085. 1 (which corresponds to U.S. Pat. No. 3,747,559) discloses that a silicon tube closed at one end may be manufactured by gas phase deposition from a hydrogen silico-chloroform mixture at about 1200.degree. C. on a graphite tube or mandrel, following which the graphite mandrel or carrier member is removed without destroying the so-deposited silicon layer. Tubes of this type are in use for diffusion doping and/or annealing procedures in semiconductor technology.